I have an Intel C2D E8400 and 2GB of ram system.
The other week I tried compiling a database using airolib-ng using my AP's SSID and a 135mb wordlist file. I did it by using the USB version of BT3 and booting into it. Even this took about 9-10 hours just to complete.
How much slower do you think it would be if I did it in a virtual machine, specifically using VirtualBox and the same USB BT3 ISO?